schizophrenia- biological explanations

Question 1

biological explainations

Answer 1

genetic factors
neural correlates
the dopamine hypothesis

Question 2

genetic factors

Answer 2

genetics are problematic not deterministic
schizophrenia is polygenic, meaning it requires a number of factors to work in combination. there are a number of genes that seem to increase the risk of schizo but only by a small amount on their own.

Question 3

human genome studies- genetics

Answer 3

ripke et al combined data from prev studies looking at whole genetic make uo of 37,000 individuals w schizophrenia compared to people without schizophrenia.

found that there were 108 separate genetic variations all associated with schizophrenia

Question 4

family studies-genetics

Answer 4

grottesman looked at the likelihood of developing schizophrenia depending on wether different biological relatives suffered from disorder and found that identical twins had 48% risk, siblings had 9% and children 13%, compared to general population risk of 1%.

Question 5

twin studies- genetics

Answer 5

Joseph pooled the data for all the studies prior to 2001 that had assessed the concordance rates among identical and non identical twins.
overalll, concordance rates for mz identical twins was 40% and the rate for dz was only 7%

Question 6

eval for genetics

Answer 6

there is evidence from adoption studies that supports the roles of genes rather than the environment.

tienari srudied adopted children who had a biological mother with schizophrenia. despite not being raed by the mothers, and therefore no environmental influence, these children were sig more likely to develop schizo 6% compared to adopted children not having schizo mothers. 24%

this finding inc the validity of the idea that schizo may be genetic is not simply down to environmental factors.

Question 7

eval for genetics

Answer 7

there are alternative explainations for the findings of twin and family studies that do not support the role of genetics.

schizo appears to run in families may be more to do with common rearing patterns or shared environments. the reason why a sibling go a schizophrenic is more likely to develop than half sibling is bc siblings are more likely to live together.
this reduces the validity of the idea that schizophrenia may be genetic, suggesting instead that environmental factors may be more important.

Question 8

eval for genetics

Answer 8

some twin/family studiy findings actually contradict the role of genetics.

grottesman family study, the risk of developing schizophrenia, if an identical twin had the disorder was 48%. similarly in Jospeh twin studies, the concordance rate among identical twins was 40%. we would expect these figures to be much higher given that identical twins share 100% of their genes.

this reduces the validity of the idea that genes are the sole cause of schizophrenia, suggesting they may actually be only a contributing factor.